In RazorCompiler, support string-valued attributes

src/Microsoft.Blazor.Build/Core/RazorCompilation/Engine/BlazorIntermediateNodeWriter.cs

@@ -148,6 +148,16 @@ namespace Microsoft.Blazor.Build.Core.RazorCompilation.Engine
                                     .WriteEndMethodInvocation();
                             }
 
+                            foreach (var attribute in nextTag.Attributes)
+                            {
+                                context.CodeWriter
+                                    .WriteStartMethodInvocation($"{builderVarName}.{nameof(RenderTreeBuilder.AddAttribute)}")
+                                    .WriteStringLiteral(attribute.Key)
+                                    .WriteParameterSeparator()
+                                    .WriteStringLiteral(attribute.Value)
+                                    .WriteEndMethodInvocation();
+                            }
+
                             if (nextToken.Type == HtmlTokenType.EndTag
                                 || nextTag.IsSelfClosing
                                 || htmlVoidElementsLookup.Contains(nextTag.Data))

test/Microsoft.Blazor.Build.Test/RazorCompilerTest.cs

@@ -157,6 +157,19 @@ namespace Microsoft.Blazor.Build.Test
                 node => AssertNode.Element(node, "img", 1));
         }
 
+        [Fact]
+        public void CanRenderAttributes()
+        {
+            // Arrange/Act
+            var component = CompileToComponent("<elem attrib-one=\"Value 1\" a2='v2' />");
+
+            // Assert
+            Assert.Collection(GetRenderTree(component),
+                node => AssertNode.Element(node, "elem", 2),
+                node => AssertNode.Attribute(node, "attrib-one", "Value 1"),
+                node => AssertNode.Attribute(node, "a2", "v2"));
+        }
+
         private static bool NotWhitespace(RenderTreeNode node)
             => node.NodeType != RenderTreeNodeType.Text
             || !string.IsNullOrWhiteSpace(node.TextContent);

test/testapps/BasicTestApp/RedTextComponent.cs

@@ -1,20 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using Microsoft.Blazor.Components;
-using Microsoft.Blazor.RenderTree;
-
-namespace BasicTestApp
-{
-    public class RedTextComponent : IComponent
-    {
-        public void BuildRenderTree(RenderTreeBuilder builder)
-        {
-            builder.OpenElement("h1");
-            builder.AddAttribute("style", "color: red;");
-            builder.AddAttribute("customattribute", "somevalue");
-            builder.AddText("Hello, world!");
-            builder.CloseElement();
-        }
-    }
-}

test/testapps/BasicTestApp/RedTextComponent.cshtml

@@ -0,0 +1 @@
+<h1 style="color: red;" customattribute="somevalue">Hello, world!</h1>